The present application relates to a method and a device for the detection of heavy metal ions in water. More specifically, the present application relates to a method for the detection of lead (Pb), mercury (Hg) and cadmium (Cd), or heavy metal ions of other types in aqueous solution employing a detection material, and a device for the detection of heavy metal ions in water based on the method.
Heavy metal ions, in particular those at a certain concentration, can lead to heavy metal poisoning, which causes illness or toxicity to human, such as dysfunction of nerve system, change in blood composition, heart and lung diseases, and the like. In recent years, analytical method and isolation technique have been developed to identify heavy metal contamination.
A variety of methods, including atomic absorption spectrometry, inductively coupled plasma-mass spectrometry, spectrophotometry (e.g., based on heavy metal-dithizone chelation) and electrochemical methods (e.g., anodic stripping analysis) have been widely used for quantitatively detecting heavy metal ions with micro even trace concentration. However, most of these methods have been limited by, for example, the need for expensive instruments, laboratory apparatus, high operating cost and/or expertise on analytical technique from the personnel.
Strip test is one of the most simple and economic methods for the semi-quantitative detection of heavy metal ions in aqueous solution. The strip test mechanism is that heavy metal chromogenic agents (such as dithizone and the like) form complexes with various types of heavy metal ions, which exhibit different colors, and the colors and the tone correlate with the concentrations of the heavy metal ions. For example, a test strip using dithizone as a heavy metal chromogenic agent can semi-quantitatively detect Cd2+ (also referred to as Cd(II) herein), Pb2+ (also referred to as Pb(II) herein) and Hg2+ (also referred to as Hg(II) herein), and the like. However, these heavy metal chromogenic agents not only chelate the heavy metal ions, but also complex with other ions such as Ca2+ (also referred to as Ca(II) herein), Mg2+ (also referred to as Mg(II) herein) or Fe3+/Fe2+ (also referred to as Fe(III)/Fe(II) herein), and the like. Therefore, when detecting heavy metal ions such as Cd(II), Pb(II) and Hg(II), and the like, many masking agents are required to prevent the reaction between dithizone with the non-heavy metal ions in the system, which complicates the experimental operation. Moreover, some of the masking agents are very toxic chemicals (such as potassium cyanide).
Therefore, developing a highly efficient detection system which is not only sensitive and reliable but also simple, convenient, economical and practical as well as suitable for the in situ detection of heavy metal ions in common aqueous environments is actually more and more desirable. There is still a desire for a new method or material which can safely and simply detect heavy metal ions in aqueous solution.